Filament tensioning apparatus

ABSTRACT

An automatic wire tensioning device for regulating the tension in a filament on a rotatable pulley during reeling and unreeling operations. The braking force on the pulley is controlled by a friction brake which is operated by a force balancing lever actuated by a braking spring and a wire tension spring. The braking spring has an adjustable loading and the wire tension spring senses the actual tension on a wire wound around and frictionally engaged with the pulley in an interdependent manner.

United States Patent Gerest Dec. 26, 1972 s41 FILAMENT TENSIONING APPARATUS 2,896,435 7/1959 Berg ..242/1s4 x 2,983,468 "5/1961 Pcrrella ..L ..242/l56.2 [72] Inventor. Marcel A. M. Gerest, Pans, France 3,023,979 3/1962 Megens et a] h D "242/155 R Assignee; Sofie Respgnsabflfle Lhnflge 3,412,948 ll/l968 P016 ..242/45 FOREIGN PATENTS 0R APPLICATIONS [221 1970 1,241,232 8/1960 France ..242/1ss R [211 Appl. No.: 41,044 Primary ExaminerStanley N. Gilreath [30] Foreign Application Priority Data Attorney-Emma & van K May 28, 1969 France ..6917286 [5 ABSTRACT An automatic wire tensioning device for regulating the [2%] V tension in a filament on a rotatable pulleyduringlreek d s l ing and unreeling operations. The braking force on the 1 o f 14 1 pulley is controlled by a friction brake which is r l 5 154 operated by a force balancing lever actuated by a braking spring and a wire tension spring. The braking [56] m Cited spring has an adjustable loading and the wire tension UNITED STATES PATENTS spring senses th e actual tension on a wire wound 1 around and frIct1onally engaged w1th the pulley In an 1,671,976 6/1928 Avery ..242/ 156.2 interdependent manner, 1,733,834 10/1929 Steele ..242[156.2 2,714,494 8/1955 wentz ..242/155 R 6 Claims, 2 Drawing Figures FILAMENT TENSIONING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic device for regulating wire or thread .tension during reeling and unreeling in winding, spooling, reeling or unreeling machines, twisting frames and generally in all appliances wherein it is necessary to ensure the constant tension of a predetermined value on a thread or wire while passing through said device.

2. Description of the Prior Art The invention concerns, in particular, braking arrangements for automatic wire tension regulators which operate during winding and unwinding andcomprise a wire-tensioning device and adevice measuring the resulting tension, the two-mechanisms inter-reacting continuously and progressively in such manner as to maintain the tension of the wire at a prescribed value; Such devices'are for example described in the French Pat No. 1,241,232 and its First Addition, No. 76,577. These devices comprise, in particular, a drum or pulley to which a wire to be handled is frictionally connected and to which a resisting-torque is applied by two plates or discs, the one rotating and the other fixedj The plates are made of suitable materials and forced against each other by a load, the value of which depends on the action of a dynamometric device continuously measuring the tension at which the wire is delivered from the appliance.

One feature of the prior art devices is that there is no reciprocal reaction between the resisting torque and.

spring. A second force is also applied to the lever mechanism. The second force is generated by a dynamometric system comprising a second spring and said second force acts in the opposite direction to said first force. The second force varies with the tension of the wire to be handled. Variations in the magnitude of the second force are transmitted tothe braking system in such a manner that the braking system is actuated to 0 reset the wire tension to its required initial value. Thus,

if wire tension increases the second force applied by said second springalso increases in the opposite direction to the first braking force and the braking torque will accordingly increase thereby reestablishing 1 BRIEF DESCRIPTION OF THE DRAWINGS The numerous objects and advantages of the present invention will be more clearly apparent from the following description of apreferred embodiment of the invention illustrated by the accompanying drawing wherein like reference numbers refer to like elements the signal controlling the torque value, the latter being controlled solely by the indications of the dynamo metric device.

Although the prior art devices briefly described above provided satisfactory results for a number-of applications, as the speed of passage of the wire and the wire tension increase, both operating characteristics causing an increase in the amount of heat generated, the performance of the prior art devices decreases significantly to an undesirable level. In addition, the prior art devices have a relatively slow response thereby producing undesirable variations in wire tension.

It is accordingly an object of the present invention to remedy the disadvantages of the already known forms of prior art wire tensioning devices.

SUMMARY OF THE INVENTION The present invention relates to an automatic device for regulating the tension of one or more wires to allow reeling or unreeling to proceed under constant tension. The invention is characterized by a braking device with a fixed plate or disc having an extensive heat-dissipating surface, and a rotating pulley on which one or more wires to be tensioned are frictionally engaged. The pulley has a braking surface in contact with one of the surfaces of the fixed plate, and the braking surface of the rotating pulley is applied against the fixed plate with a pressure depending on the required tension of such wire or wires.

In accordance with a particular feature of the present invention the pressure applied by the rotating pulley to the fixed plate is furnished by a lever mechanism to which a first or braking force is applied. The first force is generated by means including an adjustable braking throughout the several figures.

FIG. 1 shows a sectional view of the braking device of the automatic regulating system for tensioning a wire in accordance with the present invention;

FIG. 2 shows a portion of a wire tension sensing means and a balancing mechanism for use with the tensioning device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of the accompanying drawing, the braking arrangement according to-the invention comprises a fixed plate or disc 21 which is in heattransmitting contact with a frame or bedplate 54. The bedplate 54 has a surface area of considerable size and sufficient volume to act as a support for-the mechanical assembly and as a heat dissipator as will be described in detail below. The fixed plate 21 is in contact with a brake lining 20 under an adjustable pressure. The lining 20 is itself carried on a rotating pulley 19 on which one or more wires are wound in frictional engagement therewith, in order to maintain the wires under the required tension. A resisting torque is obtained on the pulley by pressing the assembly of the rotating pulley l9 and the brake lining 20 against the fixed plate 21.

This arrangement of the elements in the braking system having the shape of plates or discs is particularly advantageous since it prevents any reaction of the braked element on the elements controlling the braking power.

The brake plate or block 21, which is made of pearlite cast iron or other suitable material, is suitably machined to make it capable of heat transmission to the frame or bedplate 54, as described above. The frame or bedplate 54 serves as a radiator and thus ensures good dissipation of the heat produced by braking.

The brake lining or pad 20 which may be of any suitable material, such as leather, felt or plastic, is attached to the pulley 19 by rivets, cement or snaprings or in any 3 other suitable manner. The pulley 19 is mounted to a spindle housed in the brake block by means of a needle bearing 55. The pulley l9 and brake lining 20 are pressed against the brake block by means of a ball bearto a single pivotal lever, on the one hand by a braking spring 39, and on the other hand by the dynamometer associated with the spring 39, and furnishing suitable dynamic characteristics of the resisting torque through suitable choice and location of the said spring.

The invention can be applied to any machine for unreeling twisting,'preparing electric windings and, in

general, to all appliances in which it is necessary to a I maintain a constant tension on the thread or wire used, whether a textile yarn, or an electric wire, or a plurality spring 30 as'described in the French Pat. No. l,24l ,232

and its First AdditionNo 76,577.

With reference still to FlG. 20f the accompanying drawing, it will be seen that the'adjustable brake spring 39 operated by a tensioning device indicated generally at 59 exerts a desired force on the bellcrank lever 34 through the pivotal balancing lever 52, to which is also attached dynamomet'ric spring 30, providing by means of adequate selection of points of attachment on the lever.52 a suitable balancing of the forces in action, and 1 allowing suitable dimensioning of the springs. I As described in the aforementioned French patents, a force proportional to the wire tension is applied to the spring from a thread tension sensor 60 connected to the upper end of spring 30. A typical wire tension senpatents, the disclosures of which are incorporated herein by reference, comprises a jack" mechanism having a pair of angularly related arms; the mechanism being pivotable about the junction of the arms. Such a mechanism is indicated by reference numerals 27, 28 and 29 of French Pat. No. 1,241,232. The point of attachment of the spring 30 to one of the arms is adjustable, in the French patent'by means of mechanism'3l, and the end of the opposite arm is provided with'an idler pulley. The wire being handled is passed over the idler pulley and thedesired tension is set by adjusting the point of connection between spring 30 and the opposite arm of the pivotal jack assembly.

. in operation, lever 52 pivots about axis or pivot point 58 and bears-against the horizontal arm of bell crank lever 34'by means of steel pins or projections 65. The braking force exerted by spring 39 depends upon the spring tension which can be regulated by means of a knob 66 via a toggle lever 67. After the apparatus has been putinto service, a second force opposite to the braking'force is applied to lever 52 by means of spring 30. The magnitude of this second force is dependent upon the value selected for the wire tension; i.e., the

' second force, is selected from graduations provided along arm 28 of French Pat. No. 1,24l ,232. if the force applied by spring 39 has been adjusted correctly; the braking pulley 19 turns during reeling of the wire off a storage drum and the present tension or second force is automatically maintained. According to a particular feature of the invention, a compensating spring53 is further-provided, attached to the lever 52, which allows the regulating range to be increased by balancing the gravitational loads oi weights of the several elements 'sor of the type described in the aforementioned French of such threads or wires, as for instance, a combination of threads or wires of different kinds.

What is claimed is: 1. Apparatus for automatically regulating the tension of a filament being wound on a rotatable reel compris- I being in heat dissipating contact with said frame means; adjustable means for generating a braking force; means resiliently coupling said braking force generating means to said mounting means for causing axial motion of said pulley with respect to said frame means whereby a'preselected degree of frictional contact between said braking element and pulley braking surface may be established, said resilient coupling means including: force balancing lever means,said lever meansrineluding an elongated lever having a pivot point and a first point displaced along said lever between said pivot point and a first end of said lever, said first point being mechanically coupled to said mounting means; and

' spring means connecting a second point along said lever to said adjustable braking force generating means,- said spring means including a first resilient element and said second point being on i the same side of the pivot about which said lever means pivots as said first point whereby said first resilientelement will urge said lever first point into operative engagement with said mounting means; and means for applying an adjustable preselected tensioning force to said coupling means in opposition to said braking force whereby the braking force and selected tensioning force will be balanced. 2. The apparatus of claim 1 further comprising: a means for generating and applying'a compensating force to said coupling' means, said compensating force balancing gravitional loads' and damping vibrations. 1 i Y 3. The apparatus of claim 2 wherein said compensating force generating means comprises:

resilient means, said resilient means acting in opposition to said spring 'means. A v 4 The apparatus of claim 1 wherein saidv mounting means comprises: 1

bell crank means mounted for rotation on said frame means, a first arm of said bell crank means being mechanically coupled to said force balancing lever means;- tubular axle means extending from said frame means; means mounting said pulley means for rotation about and along said axle means; connecting rod means mechanically coupled to the second arm of said bell crank means and extending coaxially of said axle means, said connecting rod means being movable axially of said pulley means; and means mechanically coupling said connecting rod means to said pulley means whereby rotation of said bell crank means will cause axial movement of said pulley means thereby varying the operative mechanically coupled to said force balancing lever means;

tubular axle means extending from said frame means;

means mounting said pulley means for rotation about and along said axle means;

connecting rod means mechanically coupled to the second arm of said bell crank means and extending coaxially of said axle means, said connecting rod means beingmovable axially of said pulley means; and

means further comprises:

brake lining means mounted on said pulley braking surface. 

1. Apparatus for automatically regulating the tension of a filament being wound on a rotatable reel comprising: pulley means, said pulley means including a pulley having a braking surface on one side thereof, the filament being wound passiNg about and frictionally engaging said pulley; frame means; means mounting said pulley means from said frame means, said mounting means permitting axial and rotational movement of said pulley means; brake means affixed to said frame means, said brake means including a non-rotatable braking element positioned in operative relationship with the braking surface on said pulley, said braking element being in heat dissipating contact with said frame means; adjustable means for generating a braking force; means resiliently coupling said braking force generating means to said mounting means for causing axial motion of said pulley with respect to said frame means whereby a preselected degree of frictional contact between said braking element and pulley braking surface may be established, said resilient coupling means including: force balancing lever means, said lever means including an elongated lever having a pivot point and a first point displaced along said lever between said pivot point and a first end of said lever, said first point being mechanically coupled to said mounting means; and spring means connecting a second point along said lever to said adjustable braking force generating means, said spring means including a first resilient element and said second point being on the same side of the pivot about which said lever means pivots as said first point whereby said first resilient element will urge said lever first point into operative engagement with said mounting means; and means for applying an adjustable preselected tensioning force to said coupling means in opposition to said braking force whereby the braking force and selected tensioning force will be balanced.
 2. The apparatus of claim 1 further comprising: means for generating and applying a compensating force to said coupling means, said compensating force balancing gravitional loads and damping vibrations.
 3. The apparatus of claim 2 wherein said compensating force generating means comprises: resilient means, said resilient means acting in opposition to said spring means.
 4. The apparatus of claim 1 wherein said mounting means comprises: bell crank means mounted for rotation on said frame means, a first arm of said bell crank means being mechanically coupled to said force balancing lever means; tubular axle means extending from said frame means; means mounting said pulley means for rotation about and along said axle means; connecting rod means mechanically coupled to the second arm of said bell crank means and extending coaxially of said axle means, said connecting rod means being movable axially of said pulley means; and means mechanically coupling said connecting rod means to said pulley means whereby rotation of said bell crank means will cause axial movement of said pulley means thereby varying the operative relationship between said pulley braking surface and said braking element.
 5. The apparatus of claim 3 wherein said mounting means comprises: bell crank means mounted for rotation on said frame means, a first arm of said bell crank means being mechanically coupled to said force balancing lever means; tubular axle means extending from said frame means; means mounting said pulley means for rotation about and along said axle means; connecting rod means mechanically coupled to the second arm of said bell crank means and extending coaxially of said axle means, said connecting rod means being movable axially of said pulley means; and means mechanically coupling said connecting rod means to said pulley means whereby rotation of said bell crank means will cause axial movement of said pulley means thereby varying the operative relationship between said pulley braking surface and said braking element.
 6. The apparatus of claim 5 wherein said pulley means further comprises: brake lining means mounted on said pulley braking surface. 